Question

which statement best describes the relationship between an allele and a gene?
a gene is the recessive form of an allele.
a gene is the codominant form of an allele.
an allele is a variant of a gene.
alleles combine to form genes.

Explanation:

A gene is a segment of DNA that codes for a specific trait. Alleles are different forms of the same gene. For example, the gene for flower color in pea plants has alleles for purple and white. Recessive and codominant are terms related to how alleles interact, not the relationship between allele and gene. Also, genes are not formed by combining alleles; alleles are variants of a single gene.

Answer:

An allele is a variant of a gene.